Seat, especially an airplane or vehicle seat

ABSTRACT

The invention relates to a seat, especially an airplane or vehicle seat, comprising a seat part which is placed on a stand-type seat structure ( 12 ) in relation to a base and which is provided with a bearing part ( 18 ) on the front side thereof. The bearing part ( 18 ) is embodied in a flexible manner and can move in the direction of the seat structure ( 12 ) when a predefined seating load is exerted thereon; when the load is discharged it can move back into its initial position in the opposite direction from the seat structure ( 12 ), thereby creating a seat whose front part is maintained in a flexible manner such that the front area of the seat part yields according to the respective seating load exerted by the seat user and the pressure forces are thus limited to the lower side of the upper thighs of the seat user. As a result the cross-sections of the veins in said region are not reduced; the cross-sections thereof are maintained and the circulation of the blood is not impeded, thereby significantly reducing the risk of thrombosis.

The invention relates to a seat, especially an airplane or vehicle seat, with a seat part which is mounted upright on a seat structure relative to the floor and which is provided with a supporting part on its front.

Especially on very long passages, such as long-distance flights, but also on cruises, for example by means of ferries, a general object of the aircraft and ferry outfitters is to increase the comfort of seat occupants and accordingly of the passengers who are to be transported. Especially in first class and business class the customers have corresponding ideas about what they want, which wishes are to be satisfied. There is also a trend among passengers to be able to use the travel time for meaningful rest or sleeping, in order for example to effectively counteract jet lag at the destination for long-distance flights or the like.

DE 100 91 484 A1 discloses a vehicle seat, especially an aircraft passenger seat, with a seat part and backrest which are held to be able to move relative to one another by way of at least one adjustment device. In that, in the known solution, the respective adjustment device has several articulations which are connected to one another at least partially by way of a rod supporting framework as the seat structure, which bears the seat part and which executes traversing motion by an actuating means such that the seat part can be moved out of an initial position into other positions which are used for resting and sleeping and vice versa, depending on the number of attached articulations and rod parts of the rod supporting framework, the number of possibilities for movement and therefore the degrees of freedom of movement for the seat part are greatly increased compared to known solutions, so that positioning of the seat part and backrest is possible within very wide adjustment ranges. In that the known seat has pivoting leg and foot rests, the bottom of the leg area, especially the bottom of the thigh of the seat occupant, can be relieved, so that harmful pressure which reduces the cross section of the veins and thus the danger of thromboses are reduced. Based on the price structure of the pertinent seats and with respect to their space and weight requirement, they are used essentially only in first class and business class and cannot be easily used for economy class. Furthermore, with the known seat design, likewise the veins are exposed to strain, especially for the case in which the seat is in the upright (take-off position) and the leg and foot rests which relieve the cross sections of the veins folded down for the corresponding support and relief are then not available.

On the basis of this prior art, the object of the invention is to devise a seat, especially an aircraft or vehicle seat, which can be universally used and which does not have the described disadvantages in the prior art, especially helps avoid the danger of thromboses for long passages. This object is achieved by a seat with the features of claim 1 in its entirety.

In that, as specified in the characterizing part of claim 1, the supporting part is made flexible and at a definable seat load can be moved in the direction of the seat structure, and when unloaded moves back in the reverse direction away from the seat structure into its initial position, a seat is devised with a front area which is flexibly held, so that depending on the respective seat load applied by the seat occupant, the front area of the seat part yields and in this way reduces the compressive forces on the bottom of the thigh of the seat occupant, with the result that the cross sections of the veins in this area are not reduced, but their cross section is in turn maintained with the result that blood circulation is not disrupted and thus the risk of thrombosis is clearly reduced. With the solution as claimed in the invention a maximum support area of the thigh in any seat position is consequently achieved while avoiding compressive forces mainly in the forward area of the bottom of the thigh, and furthermore harmful shearing forces on the bottom of the thigh are also avoided. The pertinent shearing forces which are to be reduced arise especially in the area of the thigh in the reclining position compared to the upright seat position (take-off position) in which a more radically set seat angle is necessary. It is this greater seat angle which however causes an increase in the pressure on the bottom of the thigh when the legs are extended (slough position), with the already described danger of increasing the risk of thrombosis for the seat occupant. The occurrence of these shear forces is reliably avoided by the yielding capacity of the front area of the seat part.

The pertinent “healthy seat” can also be used in the area of motor vehicles, for example for busses; other applications are however conceivable in the area of medical treatment chairs, and in dentistry. Furthermore the comfort of the seat also increases for those seats which are equipped with pivoting leg and foot rests for relieving the bottom of the thigh. Comfort for these seats, certainly in the upright position, can also be further enhanced in this way.

In one preferred embodiment of the seat as claimed in the invention, the flexible supporting part is designed as a spiral spring which can be freely moved with one end and with its other end is fixed on elements of the seat part and/or of the support structure. If this spiral spring is designed as a rectangular leaf spring, this can be regarded as a loaded, free rest, the bending stress assuming its highest values at the bearing point and decreasing uniformly with increasing distance from the latter. Preferably the supporting part in its flexible configuration is made of a thermoplastic, but preferably of a fiber composite, especially a fiber composite fabric which is furthermore preferably an integral component of a seat shell which bears the foam cushion of the seat part and in this way also contributes to the comfort of sitting for the seat occupant.

Other advantageous embodiments are features of the other dependent claims.

The seat as claimed in the invention is detailed below using one embodiment as shown in the drawings in which in the form of diagrams and not drawn to scale:

FIGS. 1 and 2 each show a side view of the seat part, once without load application, and once with load application, shown by the force arrow F;

FIG. 3 shows a perspective corresponding to FIGS. 1 and 2 in an configuration on top of one another, and

FIG. 4 shows a perspective corresponding to FIG. 3 without the foam cushion likewise in an configuration on top of one another.

The seat as claimed in the invention is configured especially as an aircraft seat, preferably a passenger seat. As shown in FIG. 1, in a side view, essentially only the seat part of the overall seat is shown there, which part is designated as a whole as 10. In particular, for the sake of simplification the backrest and/or any foot and leg rests are not shown. The pertinent seat part 10 is accordingly mounted upright, relative to a vehicle floor or aircraft cabin deck which is not detailed, vertically by way of the seat structure 12. Of the actual seat structure 12, as shown in FIG. 1, only the two upper cross members are shown as support members 14, 16. On its front in the area of the front support member 14 the seat part 10 has a flexibly made supporting part 18 which at a definable seat load F (cf. arrow in FIG. 2) moves in the direction of the seat structure 12, especially in the form of the front support member 14. When relieved accordingly, the flexible supporting part 18 consequently returns from its position shown in FIG. 2 in the reverse direction to its initial position as shown in FIG. 1, in which the bottom of the supporting part 18 assumes a definable distance to the top of the front support member 14, the pertinent distance not having to be guaranteed over the entire width of the supporting part 18, but it can preferably suffice to ensure this distance in the area of the support of the bottom of the thigh of a seat occupant; this will be detailed below.

The flexible supporting part 18 is designed as a spiral spring which can be freely moved with one end 20 and with its other end 22 can be fixed on elements of the remaining seat part 10, as is shown in the figures, and/or alternatively also on parts of the seat structure 12. Furthermore, to obtain the indicated bending or leaf spring characteristic, the supporting part 18 is designed as a flexible support plate and can consist for example of sheet metal material. For reasons of safety engineering and for reasons of saving weight, however the indicated support plate consists preferably of a thermoplastic material, its having been found to be especially advantageous to form the supporting part 18 from a fiber composite material, for example in the form of a fiber composite fabric of carbon fiber, kevlar, or the like. Metallic leaf spring parts can also be laminated into the fiber composite for support at the same time.

From the standpoint of production engineering it has proven especially advantageous to form the supporting part 18 as an integral component of the actual seat shell 24. This seat shell 24 is shown particularly in FIG. 4 in an overhead perspective and with an integral configuration the plate-like supporting part 18 extends along the front transverse side 26 of the seat shell 24. This seat shell 24 is used in particular to hold the foam cushion 28 which enhances comfort and which consists preferably of a noncombustible polyurethane foam. As FIGS. 1 to 3 furthermore show, the foam cushion 28 with a catch-like projection 30 overlaps the flexible supporting part 18 along its front end 20, so that the supporting part 18 is essentially an integral component of a recess, extending on the bottom of the polyurethane foam cushion 28.

In order to compensate in relative terms for the length between the foam cushion 28 and the seating part 18, in the area of the supporting part 18 the foam cushion 28 merely rests there and is otherwise held in the seat shell 24. On the opposite side of the overlap of the foam cushion 28 on the supporting part 18, with the corresponding force loading (force arrow F) it can be supported with its bottom on the top of a support site, formed by the transversely extending front support member 14. The indicated support site can be formed, in contrast to the drawing in FIG. 2, by the entire support surface of the top of the front support member 14; but the possibility exists of providing, extending transversely to the front support member 14, the plate-like supporting part 18 in the direction of its center with an increasing bulge with the result that in this area the spring stiffness of the supporting part 18 is greatest and decreases to the outside toward the support sites on the front support member 14. Thus, there is especially gentle application of force, since, depending on the seat load, due to the thigh support towards either end of the front support member 14 a sliding motion takes place. It is also possible alternatively or in addition to achieve the desired center bulge by way of the configuration of the front support member 14.

Furthermore, seen in the direction of looking at FIG. 2, in the loaded state the supporting part 18 is configured to extend slightly curved so that in the area of the support or rest a relative sliding motion between the supporting part 18 and the front support member 14 is achieved in the longitudinal direction of the support part 10. This curvature in the loaded state, as is furthermore shown in FIG. 2, is simultaneously received into the front wall area of the seat shell 24, so that in this way harmonic force application occurs in the area of the transition 26 from the supporting part 18 to the seat shell 24.

The seat structure 12 furthermore has a rear support member 16 which likewise extends transversely to the seat part 10 along its back end, by way of this additional support member 16 the seat part 10 being securely connected to the seat structure 12. But if for the seat adjustment motion what is desired is that the seat part 10 moves in relative terms against the stationary seat structure 12 with its two support members 14, 16, by way of a corresponding lateral guide (not shown) this can likewise be achieved without adversely affecting the function of the resilient supporting part 18. As FIG. 1 furthermore shows, in the unloaded state the supporting part 18 forms a surface which rises in the direction of the front edge of the seat; for the seat occupant especially in the take-off phase with the backrest raised this offers good support. This rising surface of the seat part is maintained at least over the top of the polyurethane foam cushion 28 even if, as shown in FIG. 2, due to the load by the thigh the supporting part 18 is lowered for purposes of support on the top of the front support member 14.

The flexible front edge of the seat as claimed in the invention has the advantage that accordingly with a relatively small foam thickness of the foam body 28 which promotes a reduction of weight, a high degree of adaptation to the seat occupant is ensured. Due to the flexible yielding capacity of the supporting part 18 shearing forces in the area of the thigh are also greatly reduced in the reclining seat position and otherwise the cross sections of the veins are relieved accordingly so that the risk of thrombosis drops distinctly. 

1. Seat, especially an airplane or vehicle seat, with a seat part (10) which is mounted upright on a seat structure (12) relative to the floor and which is provided with a supporting part (18) on its front, characterized in that the supporting part (18) is made flexible and at a definable seat load (F) can be moved in the direction of the seat structure (12), and when unloaded moves back in the reverse direction away from the seat structure (12) into its initial position.
 2. The seat as claimed in claim 1, wherein the flexible supporting part (18) is designed as a spiral spring which can be freely moved with one end (20) and with its other end (22) is fixed on elements of the remaining seat part (IO) and/or of the seat structure (12).
 3. The seat as claimed in claim 2, wherein to retain the spiral spring characteristic the supporting part (18) is formed as a flexible support plate from sheet metal. material and/or from thermoplastic and/or from a fiber composite.
 4. The seat as claimed in claim 1, wherein the supporting part (18) is an integral component of a seat shell (24) which bears the foam cushion (28) of the seat part (10) and wherein the foam cushion (28) overlaps the supporting part (18) on its one side and wherein on the opposite, other side the seat structure (12) forms at least one support site for the supporting part (18).
 5. The seat as claimed in claim 4, wherein the seat structure (12) which forms the respective support site forms a support member (14) which is designed convex at least on its side facing the supporting part (18), and in this way allows a relative sliding motion between the supporting part (18) and the support member (14).
 6. The seat as claimed in claim 4, wherein the supporting part (18) and/or the support member (14) have a bulge such that to the two free ends of one support member (14) a support site is formed there and wherein under the support load the existing bulge between the two support sites decreases.
 7. The seat as claimed in claim 5, wherein the seat structure (12) has a support member (16) which extends transversely to the seat part (10) on its back end and wherein the seat part (10) is securely connected to the seat structure (12) by way of this additional support member (16) or wherein at least the support member (14) as a type of slide bearing allows relative motion between the seat part (10) and the seat structure (12).
 8. The seat as claimed in claim 1, wherein in the unloaded state the supporting part (18) forms a surface which rises in the direction of the front edge of the seat and which in the fully loaded state extends parallel to the floor or has a curvature which is pointed to the floor. 